JPH07108458B2 - Enclosed arc welding method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an enclosed arc welding method for performing enclosed welding with a rod-shaped material to be welded such as a reinforcing bar standing vertically.

[Prior Art] The conventional enclosed arc welding method in the case of a vertical joint was performed by processing a so-called oblique I-shaped groove (Japanese Patent Publication No. 52-
No. 35624). FIG. 6 is a side view showing a conventional enclosed arc welding method in the case of a vertical joint, and FIG. 7 is its VII-V.
It is sectional drawing by the II line. In this method, for example, the deformed rebar 1 is provided with its joint surface inclined with respect to its axial direction, and the two rebars 1 are arranged vertically with a predetermined groove space provided therebetween. A pair of split type copper metal members 2 are arranged so as to surround the groove space. Then, the welding rod 3 is inserted into the groove space from the welding port 4 of the copper plate 2 received above the groove space, and the weld metal is filled from the lower part to the upper part of the groove space. As a result, the fixed vertical workpieces can be quickly and soundly joined.

In recent years, as a method of joining reinforcing bars embedded in concrete columns of reinforced concrete buildings, they must be assembled by the pre-assembly method in order to improve the efficiency of the method of joining one piece at a construction site. Is increasing. In other words, in the factory or on the ground, multiple rebars are assembled in advance, they are stacked at the construction site, and the assembled assemblies are welded in a horizontal position. It is used for things.

The above-mentioned enclosed arc welding method has the advantage that the workability of the hoop streak, which is a post-process, is good without excessively enlarging the shape of the joint joint part. It is used.

[Problems to be Solved by the Invention] However, the conventional enclosed arc welding method is
Since the weld groove has an oblique I shape, it has the following drawbacks. That is, in the case of this oblique I-shaped groove, there is a constraint that welding must be performed by inserting a welding rod into the groove from above in the extension direction of the groove surface. For this reason, in the pre-assembled rebar construction method, it is necessary to pre-assemble the rebar so that the groove will be in that direction in consideration of the direction of welding work in advance. In consideration of the welding process direction, it is necessary to process the inclined joint surfaces so that they are parallel to each other.

For this reason, it is necessary to strictly control the direction of the reinforcing bars during pre-assembly, and despite the fact that the pre-assembly method is adopted for the purpose of speeding up and improving efficiency, the work is actually extremely complicated and inefficient. There is a problem that is.

In addition, inclining the joining surface of the reinforcing bar with respect to the axis, the process is complicated and the amount of cutting is increased,
There is a problem that the yield decreases. Furthermore, when this groove processing is performed by gas cutting on site, gas notches are likely to occur, and there is a disadvantage that much labor is consumed in the grinder grinding work of the groove surface (bonding surface).

The present invention has been made in view of such problems,
The joint surface of the groove is easy to process, the groove processing time is shortened, there is no restriction on the front assembly, and the front assembly can be done quickly and easily. It is an object of the present invention to provide an enclosed arc welding method that can make the soundness of the factory a factory, can easily determine the quality of the result by an appearance inspection, and enable highly efficient welding work.

[Means for Solving the Problems] The enclosed arc welding method according to the present invention has a pair of materials to be welded, each of which has a rod shape and whose joint surface is substantially perpendicular to its axial direction. Arranged vertically with a predetermined groove space, this material consisting of a refractory material having a softening point of 1100 ° C or higher is brought into contact with the side surface of the material to be welded below, and this material and the material to be welded above. Between the two, the gap is 2mm or more and half or less of the interval between the joint surfaces of the upper and lower workpieces, and is disposed so as to surround a part of the groove space, then, Characterized by arc welding between the joint surfaces.

Incidentally, the joint surface is substantially perpendicular to the axial direction of the rod-shaped material to be welded, when performing welding by the method of the present invention,
It means that there is no inclination that limits the mounting position of this material and the insertion position of the molten material, etc.In other words, there is no problem in terms of inclination without considering the directionality of welding in construction. included.

Further, when this material is overlapped on the side surface of the material to be welded below, it is not necessary to contact this material with the material to be welded over the entire area of the overlapped material, and contact is made with a part of that area. Just do it. Further, it is needless to say that this material does not need to contact the entire side surface of the material to be welded below.

[Operation] In the present invention, a horizontal groove is provided, and the material is placed in contact with the side surface of the lower member to be welded. This material surrounds a part of the groove space and is arranged with a predetermined gap between it and the material to be welded above. Then, for example, a bridging portion is formed by welding weld metal from the lower side of the material to be welded near the material.

In this case, since the material is disposed on the far side of the groove, the end of the joint surface of the materials to be welded does not burn through at the start of welding. Further, by using this material, a bridging portion can be easily provided between the joint surfaces of the upper and lower materials to be welded. Further, since the slag floats upward and is formed between the material and the material to be welded above and discharged from the gap, the slag does not remain in the welded portion between the joint surfaces.

Furthermore, this material has a softening point of 1100 ° C or higher (Zegel cone
Since it is molded with a refractory of SKO1a or more), even if it contacts molten metal melted by arc heat, it can receive the molten metal through the slag, and the integrity of the start part where defects are most likely to occur It becomes easy to improve.
Therefore, after welding, this material can be collected and reused, and since this material has separated after welding, it is possible to easily visually observe the appearance and properties of the welded part, and to check for defects. It can also be determined. In addition, since the contact surface of the welded part that is in contact with the refractory material is smooth, a beautiful welded part can be obtained.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings. 1 (a) to 1 (e) are schematic diagrams showing an enclosed arc welding method according to an embodiment of the present invention in process order,
FIG. 2 is a sectional view taken along line II-II of FIG.

The upper reinforcing bar 11 and the lower reinforcing bar 12 have their joint surfaces substantially perpendicular to the axial direction. Therefore, when the reinforcing bars 11 and 12 are arranged vertically with their axial directions aligned, the quantity joint surface is Are substantially horizontal and parallel to each other. The copper metal plate 14 has a U-shaped horizontal cross section, and is arranged so as to hold the reinforcing bars 11 and 12 around a groove space 15 formed between the upper reinforcing bar 11 and the lower reinforcing bar 12. Both of the reinforcing bars 11 and 12 are held by a pair of clampers (not shown) fixed to a copper plate 14 so that their opposite ends have the same axis. It is arranged so as to face up and down via the 14 and the clamper.

Behind the groove space 15 between the reinforcing bars 11 and 12, there is a recess 16 in the copper plate 14
Is formed, and the material 13 is disposed in the recess 16 in contact with the side peripheral surface on the back side of the lower reinforcing bar 12. The strip 13 is fixed by being pressed against the lower rebar 12 from behind by a bolt 17 that horizontally penetrates the copper strip 14.

The material 13 is preferably a non-metal refractory material such as cordierite or forsterite.

After arranging the upper rebar 11, the lower rebar 12, the bar 13 and the copper plate 14 in this way, as shown in FIG.
Insert 18 into the groove space 15 from the U-shaped open side of the copper dowel 14,
Welding is started from the vicinity of the material 13 (back side of the groove space 15). That is, first, the material 13 on the joint surface of the lower rebar 12 is
Start the arc at a position of 5 to 6 mm before, and immediately move the arc to the corner between the joint surface of the lower reinforcing bar 12 and the material 13 and perform semi-weaving while shortening the arc, and melt the molten metal. Wait for the excitement.

Then, as shown in FIG. 1 (b), the molten metal 20 is applied to the material.
Assemble on the joint surface of the lower rebar 12 using 13. In this case, the generated slag 21 floats on the molten metal 20. Then, the joining surface (upper groove) of the upper rebar 11 and the molten metal
When the distance from 20 becomes 2 to 3 mm, the semi-weaving is stopped and the arc is stopped to melt the corner portion of the upper groove and bridge it.

After the upper rebar 11 and the lower rebar 12 are bridged, as shown in Fig. 1 (c), the semi-weaving is performed and the generated slag is used in the gap between the upper rebar 11 and the bar 13. The welding rod 18 is alternately turned upward and downward while being discharged to the outside of the groove to secure the melting of the upper groove side and the lower groove side. In this way, as shown in FIGS. 1 (d) and 1 (e), the molten metal 20 is continuously laminated to the foremost part of the groove. Then
After the arc is stopped and the molten metal 20 is cooled and solidified, the clamper is removed, the material 13 is separated from the welded portion, and welding is completed.

In the method of the present embodiment, a small piece of refractory material 13 is brought into contact with the lower rebar 12 side in the inner part of the copper plate 14 to bridge the molten metal 20 between the upper rebar 11 and the lower rebar 12. To enable. Then, the I-shaped groove formed at the joint surface between the upper reinforcing bar 11 and the lower reinforcing bar 12 is arc-welded vertically. When welding is performed without using this material 13, the upper rebar 11 and the lower rebar 12 at the back of the I-shaped groove
An appropriate bridge with is formed. Because of the welding posture, the molten metal 20 only spreads on the groove surface (joint surface) of the lower rebar 12 and does not easily reach the upper rebar 11. in this way,
The small piece of material 13 has a function of depositing the molten metal 20 in the deep part of the groove and promoting bridging between the upper and lower reinforcing bars.

Further, since the material 13 is formed of a refractory material having a softening point of 1100 ° C. or higher, it does not melt even when it comes into contact with a metal melted by receiving arc heat, and does not fuse to the welded portion. Therefore, the material 13 can be easily separated from the welded portion after the welding is completed, and the appearance and properties of the exposed welded portion can be visually observed to grasp the presence or absence of defects. Further, when a vitreous refractory material is used as the material 13, a glossy and smooth surface can be obtained, and a beautiful welded portion can be obtained.

As described above, in order to form the bridging using the bar 13, the both ends of the lower bar 12 of the bar 13 in the circumferential direction are rebar.
The central angle θ with the axis of 12 must be 30 ° or more. However, if this material is too large, it will be difficult to discharge the slag 21 during the enclosed arc welding out of the groove, and it is easy to cause welding defects such as large-scale slag entrainment and fusion failure resulting from this. Become. For this reason, this material 13 has a central angle θ of approximately 150 (150/3
60) Stop so that it covers an area of less than °.

The distance d (mm) between the upper reinforcing bar 11 and the material 13 is 2 to D /
2mm However, D (mm) is the distance between the upper reinforcing bar 11 and the lower reinforcing bar 12. When d is less than 2 mm, the escape of the slag 21 becomes poor and the slag is apt to be caught. Moreover, in order to discharge the slag 21, a high degree of skill and strict monitoring of welding conditions are required. On the other hand, if d exceeds D / 2, it is difficult to form a bridging portion by the molten metal 20. Therefore, the joint is not completed.

Incidentally, in welding, the inner peripheral surface of the material 13 and the outer peripheral surface of the rebar 12 are curved with the same curvature, and the material 13 is in full contact with the rebar 12 within the range of the central angle θ described above. Is ideal. However, as shown in FIG. 3 (a), the case where the diameter of the lower reinforcing bar 12 is large and a gap a is formed between the central portion of the bar 13 and the reinforcing bar 12, and FIG. 3 (b). In some cases, the lower rebar 12 has a small diameter, and both ends of the bar 13 are separated from the peripheral surface of the rebar 12 by a distance b as shown in FIG. Also in this case, if a is about 2 mm or less and d is 2 to 3 mm, the same effect as that of contacting the lower reinforcing bar 12 on the entire surface of the material 13 can be obtained. As a result, a dedicated material for each rebar with different cross-sectional diameter
The complexity of preparing 13 can be avoided.

It should be noted that by using a material 22 having the shape shown in FIGS. 4 and 5 in place of the material 13, it is possible to form a back bead and adjust the appearance of the welded portion. The material 22 is curved in an arc shape as a whole, but the lower half reinforcement of the lower half step
A step is formed on the inner surface of the groove 12 such that the portion in contact with the peripheral surface is thick and the upper half part surrounding the groove space 15 is thin. A slight space is formed on the back side of the groove space 15 by the recess 23 formed on the inner surface of the member 22 by this step.

Therefore, even if part of the slag generated during arc welding does not float completely and stays in the lower part of the groove space, this slag escapes into the recess 23, so that the slag remains on the joint surface of the lower reinforcing bar 12. There is nothing to do. Further, the back bead of the molten metal 20 is formed in this recess 22, so that a clean weld with very few defects can be formed between the joint surfaces of the upper and lower rebars 11, 12 and the joint strength can be improved. Can be increased.

Further, in the above arc welding, molten metal may be laid in the groove space only by covered arc welding, and carbon dioxide (CO ₂ ) arc welding is performed as a part of this welding process to perform covered arc welding and carbon dioxide arc welding. You may combine and.

Next, the result of the vertical welding of the I-groove actually performed by the method of the embodiment of the present invention will be described.

Used reinforcing bar; SD35, SD40 (JIS) Reinforcing bar shape; JIS G3112 (Steel bar for reinforced concrete) Reinforcing bar diameter; D21 and D38 Welding bar; For SD35, use JISD5816 For SD40, use JISD7016 For groove spacing; D22 10mm and 14mm for case, 12m for D38
m and 16mm This material; width 25mm, length 20mm, thickness 10mm cordierite (softening point 1300 to 1400 ℃) Welding current; D38 150-170A, D22 120-130A This welding The characteristics of the welded portion obtained by welding under the conditions are shown in Table 1 below.

Both have sufficient strength and ductility.

Further, Table 2 below shows the welding results of the case where the reinforcing rod having a diameter of D41 is used for welding by the method of the embodiment of the present invention and the case where welding is performed by the conventional method by comparing the two.

As is clear from Table 2, according to the method of the present embodiment, the required time is approximately halved as compared with the conventional method, and the efficiency is extremely high.

Further, as described above, since the joining surface can be horizontal and the enclosed arc welding can be performed, when the rebar is pre-assembled,
It is not necessary to assemble the reinforcing bar in consideration of its directionality, and therefore, it is possible to quickly assemble the rebars, and the advantages of the preassembly method can be fully utilized. Further, since it is sufficient to form a joint surface substantially perpendicular to the axial direction of the reinforcing bar, it is easy to form a groove shape and the yield is high because there are few cut-off portions.

[Effect of the Invention] According to the present invention, there is an advantage that the groove shape is an I-shape that is perpendicular to the axial direction of the material to be welded, and there is no restriction on the directionality of the reinforcing bar axis to be constructed. Further, since the groove is perpendicular to the axis of the reinforcing bar, the groove can be used as it is obtained from the reinforcing bar, or can be used as it is for high speed cutting or gas cutting, and the processing is simple.

Furthermore, it is not necessary to remove slag until the end of welding, and the groove area is reduced to 70% of that of the conventional method, so welding can be performed with even higher efficiency.

Furthermore, since this material is formed of a refractory material, it can be easily separated from the welded part after welding, and the welded part where the backside wave is formed can be visually observed. It can be easily determined.

Furthermore, it is not necessary to draw the rebars to be joined together, and it is possible to construct a joint for the restrained rebars.

Also, the gap between the upper welded material and this material is 2 mm or more,
In addition, since the distance between the upper and lower joint surfaces of the materials to be welded is 1/2 or less, slag is reliably discharged from the gap between the materials to be welded and this material, and bridges are easily bridged within the groove. The part can be formed and the joint can be completed, which results in a sound joint with no welding defects.

As a result, according to the present invention, the work at the construction site can be made highly efficient, and welding can be performed at low cost.

[Brief description of drawings]

1 (a) to 1 (e) are schematic diagrams showing an enclosed arc welding method according to an embodiment of the present invention in the order of steps, and FIG. 2 is a sectional view taken along line II-II of FIG. 1 (a). Figure 3 (a),
(B) is a plane sectional view of a reinforcing bar, FIG. 4 is a perspective view showing a modified example of this material, FIG. 5 is a schematic view showing a state in which this material is also arranged in a groove space, and FIG. 6 is conventional. Side view showing the method,
FIG. 7 is a sectional view taken along line VII-VII in FIG. 11,12; Reinforcing bar, 13,22; Material, 14; Copper metal, 15; Groove space, 2
3; recess

Claims (3)

[Claims] 1. A pair of materials to be welded, which have a rod-like shape and whose joint surface is substantially perpendicular to the axial direction thereof, are vertically arranged at a predetermined groove space between the joint surfaces, and the temperature is 1100 ° C. This material consisting of a refractory material having the above softening point is brought into contact with the side surface of the lower material to be welded, and 2 m between the material and the upper material to be welded.
A gap that is equal to or greater than m and is equal to or less than 1/2 of the distance between the joining surfaces of the upper and lower workpieces is provided to surround a portion of the groove space, and then between the joining surfaces. Enclosed arc welding method characterized by arc welding. 2. Enclosed arc welding according to claim 1, wherein welding is started in the vicinity of the material and molten metal is deposited from the lower side of the material to be welded to form a bridging portion. Method. 3. The enclosure according to claim 1, wherein the material is in contact with the axis of the lower material to be welded in a region having a central angle of 30 to 150 °. Arc welding method.